Field of the Invention
The invention relates to a permanent magnet motor having reduced torque ripple.
Description of the Related Art
Typical measures to decrease torque ripple include: stator slot skewing, rotor step skewing, stator teeth notching, arc modification on the rotor surface. However, the application of the stator slot skewing or the rotor step skewing is limited to concentrated winding with relatively few slots. This is because the fewer the number of slots, the larger the axial misalignment angle that is required, which translates to a large decrease in the fundamental wave torque.
Also, although the stator teeth notching and the arc modification on the rotor surface improve the cogging torque ripple of the stator, the effect on the sixth-harmonic ripple, which is the most important to reducing the total torque ripple, is small.